Never seen a casino thrive for long without Nigerians - they are the market, and cutting them off is suicidal. It is their loss.
Maybe what you are truly finding insulting is that you know (like the rest of us) that Nigeria is known for having a higher rate of scammers per capita than other countries. India is also known to have a lot of scammers, but probably a smaller percentage of the population than Nigeria.
This is not true, but you're free to believe whenever the media sold to you. The last time I checked Russia, US, and China had higher rate of scammers than the rest of 3rd world countries.
Sometimes I wonder how the world would have reacted if the past crypto frauds and exchange hacks were tied to Nigeria.